System and method for shared vehicle tire pressure monitoring, remote keyless entry, and vehicle immobilization

ABSTRACT

A combined vehicle remote access, tire monitoring and vehicle immobilization system and method including a tire monitor for monitoring a tire parameter, the monitor including a transmitter for transmitting a radio frequency tire data signal, a vehicle access transmitter for transmitting a radio frequency vehicle access signal, and a vehicle activation transponder for receiving an interrogation signal and transmitting a vehicle activation signal for use in vehicle immobilization. The system and method further include a control module having a receiver and a controller for receiving and processing the tire data, vehicle access, and vehicle activation signals, and generating a display signal to display the information represented by the tire data signal, a vehicle access control signal to perform the vehicle access function, and a vehicle immobilization control signal to immobilize the vehicle if the controller fails to authenticate the vehicle activation signal.

TECHNICAL FIELD

[0001] The present invention relates generally to wireless vehicle tirepressure monitoring, vehicle remote keyless access, and vehicleimmobilization and, more particularly, to a system and method employinga combined receiver for shared vehicle tire pressure monitoring, remotekeyless entry, and immobilization functions.

BACKGROUND ART

[0002] It is well known in the automotive industry to provide for remotekeyless entry (RKE) to a vehicle through the use of a hand heldtransmitter, which is commonly referred to as a “fob.” Currentlyavailable RKE fobs may be separate units, or may be part of an ignitionkeyhead, preferably along with a vehicle immobilization transponder.Such RKE fobs generally utilize an antenna to transmit radio frequency(RF) signals to a vehicle in order to lock or unlock vehicle doors, openor close a vehicle sliding door, unlock a vehicle trunk, activateinternal and/or external vehicle lights, and/or activate a “panic”alarm. Remote access systems using such RKE fobs typically employ on-offkeying (OOK) or amplitude shift keying (ASK) modulation schemes for theRF signals.

[0003] It is also known in the industry to provide for wirelessmonitoring of vehicle tire parameters, particularly tire pressure. Anexemplary tire monitoring system is described and shown in U.S. Pat.Nos. 5,600,301 and 5,463,374, which also describes a vehicle remoteaccess device. In such tire monitoring systems, RF transmitters mountedinside each tire, typically adjacent the inflation valve stem, transmitinformation concerning tire pressure to a receiver located on-board thevehicle. The information delivered by the RF signals from thetransmitters is subsequently conveyed to a vehicle operator, typicallyin the form of a display. Like vehicle remote access systems, such tiremonitoring systems also typically employ OOK or ASK modulation schemesfor the RF signals. When such modulation schemes are used, however,there can be strong adverse effects on reception of the RF signal,because the amplitude of a signal transmitted from a rotating tire canvary significantly during the period of the transmission.

[0004] Finally, in order to deter theft, it is also known in theautomotive industry to provide systems for vehicle immobilization. U.S.Pat. No. 5,670,933 illustrates an example of such an immobilizationsystem. Such vehicle anti-theft devices typically employ low frequency(LF) transponders in a vehicle ignition keyhead. In such systems, uponinsertion of the vehicle ignition key into the vehicle ignition keyhole,an interrogation signal is sent by the vehicle. In response, the keyheadtransponder transmits an encrypted code to a control unit, such as amicroprocessor, on-board the vehicle. If the code sent by thetransponder is valid (i.e., the control unit authenticates the receivedcode), then the control unit generates a signal operative to permit thevehicle to be activated. However, if the code is not received by thecontrol unit, or if the code is not valid (i.e., the control unit cannotauthenticate the received code), then the control unit generates asignal operative to immobilize the vehicle, for example by cutting offthe fuel supply to the vehicle engine.

[0005] It would be desirable to provide a system and method for sharedvehicle remote access, tire monitoring and vehicle immobilization. Sucha combined system and method would provide an improved and simplifieddesign for such functionality, thereby optimizing performance andproviding a cost advantage. In particular, such a system and methodwould preferably employ a combined RKE, tire monitoring and vehicleimmobilization receiver and a single microprocessor controller. Such asystem and method would also preferably use an OOK or ASK modulationscheme for RKE, while employing a more advantageous frequency shiftkeying (FSK) modulation scheme for tire monitoring, thereby overcomingthe problems of the prior art tire monitoring systems described above.Still further, such a system and method would also preferably provide anadvantageous RF link for use in vehicle immobilization.

SUMMARY OF THE INVENTION

[0006] Accordingly, it is an object of the present invention to providea system and method for shared vehicle remote access, tire monitoringand vehicle immobilization functions in order to improve performance andreduce expense. In that regard, it is a further object of the presentinvention to preferably employ a combined remote keyless entry (RKE),tire monitoring and vehicle immobilization receiver and a singlemicroprocessor controller. It is also an object of the present inventionto preferably use an on-off keying (OOK) or amplitude shift keying (ASK)modulation scheme for RKE, while preferably employing a moreadvantageous frequency shift keying (FSK) modulation scheme for tiremonitoring, as well as to preferably provide an advantageous radiofrequency (RF) link for use in vehicle immobilization.

[0007] According to the preferred embodiment of the present invention, acombined vehicle remote access, tire monitoring and vehicleimmobilization system is provided for use with an automotive vehicle.The system comprises a tire monitor for mounting in a vehicle tire formonitoring at least one tire parameter, the monitor including atransmitter for transmitting a radio frequency tire data signalrepresenting information concerning the at least one tire parameter, ahandheld remote vehicle access transmitter for transmitting a radiofrequency vehicle access signal for use in performing at least onevehicle access function, and a vehicle activation transponder forreceiving an interrogation signal and transmitting a vehicle activationsignal for use in a vehicle immobilization function. The system furthercomprises a control module for mounting on-board the vehicle, thecontrol module including a receiver for receiving the tire data, vehicleaccess, and vehicle activation signals, and a controller for processingthe tire data, vehicle access, and vehicle activation signals andgenerating a display signal operative to display to a vehicle operatorthe information represented by the tire data signal, a vehicle accesscontrol signal operative to perform the at least one vehicle accessfunction, and a vehicle immobilization control signal operative toimmobilize the vehicle if the controller fails to authenticate thevehicle activation signal.

[0008] According to another aspect of the present invention, a methodfor combined vehicle remote access, tire monitoring and vehicleimmobilization is also provided for use with an automotive vehicle. Themethod comprises providing a tire monitor for mounting in a vehicle tirefor monitoring at least one tire parameter, the monitor including atransmitter for transmitting a radio frequency tire data signalrepresenting information concerning the at least one tire parameter,providing a handheld remote vehicle access transmitter for transmittinga radio frequency vehicle access signal for use in performing at leastone vehicle access function, and providing a vehicle activationtransponder for receiving an interrogation signal and transmitting avehicle activation signal for use in a vehicle immobilization function.The method further comprises providing a control module for mountingon-board the vehicle, the control module including a receiver forreceiving the tire data, vehicle access, and vehicle activation signals,and a controller for processing the tire data, vehicle access, andvehicle activation signals and generating a display signal operative todisplay to a vehicle operator the information represented by the tiredata signal, a vehicle access control signal operative to perform the atleast one vehicle access function, and a vehicle immobilization controlsignal operative to immobilize the vehicle if the controller fails toauthenticate the vehicle activation signal.

[0009] These and other objects, features and advantages of the presentinvention will be readily apparent upon consideration of the followingdetailed description of the invention in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

[0010]FIG. 1 is an overall block diagram of the combined vehicle access,tire monitoring and vehicle immobilization system of the presentinvention;

[0011]FIG. 2 is a simplified block diagram of the control module of thecombined vehicle access, tire monitoring and vehicle immobilizationsystem of the present invention;

[0012]FIG. 3 is a simplified flowchart of the combined vehicle access,tire monitoring and vehicle immobilization method of the presentinvention; and

[0013]FIGS. 4a-c are simplified flowcharts illustrating operations ofthe combined vehicle access, tire monitoring and vehicle immobilizationmethod of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0014] Referring to FIGS. 1-4, the preferred embodiment of the presentinvention will now be described. As previously noted, it is known in theautomotive industry to provide for remote keyless entry (RKE) to avehicle through the use of a hand held transmitter, which may be part ofa separate RKE fob, or part of a vehicle ignition keyhead with a keyheadtransponder for use in vehicle immobilization. Such transmittersgenerally utilize an antenna to transmit radio frequency (RF) signals toa vehicle in order to lock or unlock vehicle doors, open or close avehicle sliding door, unlock a vehicle trunk, activate internal and/orexternal vehicle lights, and/or activate a “panic” alarm. Such RKE fobstypically employ on-off keying (OOK) or amplitude shift keying (ASK)modulation schemes for the RF signals.

[0015] As also previously noted, it is also known in the industry toprovide for wireless monitoring of vehicle tire parameters, particularlytire pressure. In such tire monitoring systems, RF transmitters locatedinside each tire transmit information concerning tire parameter, such aspressure, to a receiver located in the vehicle, which information isultimately displayed to a vehicle operator. Like vehicle remote accesssystems, such tire monitoring systems also typically employ OOK or ASKmodulation schemes for the RF signals. With such modulation schemes,however, there can be strong adverse effects on signal reception,because the amplitude of a signal transmitted from a rotating tire canvary significantly during transmission.

[0016] Finally, as also noted previously, it is also known in theautomotive industry to provide systems for vehicle immobilization todeter theft. Such anti-theft devices typically employ low frequency (LF)transponders in a vehicle ignition keyhead. Upon insertion of thevehicle ignition key into the vehicle ignition keyhole, an interrogationsignal is sent by the vehicle. In response, the keyhead transpondertransmits an encrypted code to a control unit on-board the vehicle. Ifthe code sent by the transponder is valid (i.e., the control unitauthenticates the received code), then the control unit permits thevehicle to be activated. However, if the code is not received by thecontrol unit, or if the code is not valid (i.e., the control unit cannotauthenticate the received code), then the control unit acts toimmobilize the vehicle, for example by cutting off the fuel supply tothe vehicle engine.

[0017] As noted, it would be desirable to provide a system and methodfor shared vehicle remote access, tire monitoring and vehicleimmobilization. Such a combined system and method would provide animproved and simplified design for such functionality, therebyoptimizing performance and providing a cost advantage. In particular,such a system and method would preferably employ a combined RKE, tiremonitoring and vehicle immobilization receiver, as well as a singlemicroprocessor controller. Such a system and method would preferably usean OOK or ASK modulation scheme for RKE, while employing a moreadvantageous frequency shift keying (FSK) modulation scheme for tiremonitoring, thereby overcoming the problems of the prior art tiremonitoring systems described above. Still further, such a system andmethod would also preferably provide an advantageous RF link for use invehicle immobilization.

[0018] Referring now to FIG. 1, an overall block diagram of the combinedvehicle access, tire monitoring and vehicle immobilization system of thepresent invention is shown, denoted generally by reference numeral 10.As seen therein, the system (10) includes a tire monitor (12) formounting in a tire (14), preferably located inside the tire adjacent thetire inflation valve stem (not shown). Tire monitor (12) includesappropriate sensors and other devices for monitoring any number of tireparameters, such as tire pressure, temperature, status (i.e., whether ornot the tire is in motion) and/or speed, in any fashion well known tothose of ordinary skill in the art. Tire monitor (12) includes atransmitter (16) for transmitting a radio frequency (RF) tire datasignal (18) representing information concerning the tire pressure,temperature, status and/or speed determined by tire monitor (12), whichinformation, as described in greater detail below, is ultimatelyconveyed to a vehicle operator via a display. It should be noted that asingle tire monitor (12) is shown in FIG. 1 only for the sake ofsimplicity. It is to be understood that, according to the presentinvention, tire monitors are preferably included in each vehicle tire.

[0019] As previously noted, the amplitude of tire data signal (18)coming from a rotating tire can vary significantly during transmission.This can have strong adverse effects on the ultimate reception of tiredata signal (18) if it is encoded using on-off keying (OOK) or amplitudeshift keying (ASK) modulation. To overcome this problem, the presentinvention preferably employs frequency shift keying (FSK) modulation toencode the tire data signal. It should be noted, however, that on-offkeying (OOK) or amplitude shift keying (ASK) could also be used.

[0020] The combined vehicle access, tire monitoring and vehicleimmobilization system (10) of the present invention also includes a handheld remote vehicle access transmitter (20). As shown in FIG. 1,transmitter (20) is a remote keyless entry (RKE) fob of the typetypically employed in the automotive industry. It should be noted,however, that transmitter (20) may alternatively be included with avehicle activation transponder (26) in a vehicle ignition keyhead (30)as described below, as is also well known in the industry. RKE fob (20)preferably includes a radio frequency (RF) transmitter (22) fortransmitting an RF vehicle access signal (24) for use in performing anynumber of vehicle access functions, such as operating (i.e., locking orunlocking) a vehicle door lock, activating internal and/or externalvehicle lights, operating (i.e., opening or closing) a vehicle slidingdoor, unlocking a vehicle trunk, activating a vehicle horn, activating avehicle “panic” alarm, or other functions. In that regard, unlike thesituation with tire data signal (18), amplitude changes are not aproblem with vehicle access signal (24). As a result, frequency shiftkeying (FSK) modulation is not required for vehicle access signal (24).Instead, the present invention preferably utilizes on-off keying (OOK)or amplitude shift keying (ASK) modulation for vehicle access signal(24), although frequency shift keying (FSK) could also be used.

[0021] Still referring to FIG. 1, the system (10) of the presentinvention further includes a vehicle activation transponder (26) forreceiving an interrogation signal and transmitting a vehicle activationsignal (28) in the form of an encrypted, secret code, in a fashion wellknown in the art. In that regard, transponder (26) is located in avehicle ignition keyhead (30). As a result of insertion of the vehicleignition key into the vehicle ignition keyhole, an interrogation signalis sent from the vehicle. Upon receiving the interrogation signal,vehicle activation transponder (26) sends vehicle activation signal (28)representing the encrypted code. In that regard, vehicle activationtransponder (26) may comprise a low frequency (LF), inductively coupled,battery-less transponder such that vehicle activation signal (28) is anLF signal. As used herein, LF includes frequencies up to about 15 Mhz.

[0022] As noted above, vehicle activation transponder (26) may belocated in vehicle ignition keyhead (30) along with vehicle accesstransmitter (22). In that regard, it should be noted that a singlemicroprocessor (not shown) could be used in keyhead (30) for bothvehicle access transmitter (22) and vehicle activation transponder (26).Alternatively, a microprocessor could be used for vehicle accesstransmitter (22), while a transponder circuit could be used for vehicleactivation transponder (26). Moreover, vehicle activation transponder(26) may also alternatively comprise a radio frequency (RF) transponder,such that vehicle activation signal (28) is an RF signal. In thatregard, such an RF vehicle activation transponder (26) could beactivated to send RF vehicle activation signal (28) by an LF transponderlocated in vehicle ignition keyhead (30). As described in greater detailbelow, the encrypted code represented by vehicle activation signal (28)is used in determining whether the vehicle should be immobilized, ordisabled, such as by cutting of the fuel supply to the engine. In thatregard, an RF vehicle activation signal (28) may be advantageously usedin order to guarantee its reception by a control module (32) describedbelow, thereby preventing inadvertent or undesired vehicleimmobilization.

[0023] Referring still to FIG. 1, the system (10) also includes controlmodule (32), including a receiver (34) provided in communication with acontroller (36). Receiver (34) is operative to receive tire data signal(18), vehicle access signal (24) and vehicle activation signal (28).Controller (36) is operative to process tire data signal (18) fromreceiver (34), and to generate a display signal (38) operative todisplay the tire information represented by tire data signal (18) to avehicle operator via a display unit (40), such as an LED or lighted iconin the vehicle dashboard or a vehicle console. It should be noted thatthe information displayed to the vehicle operator may include a warning,which may also be audible, if tire pressure and/or other tireparameters, such as temperature, are outside recommended ranges.Controller (36) is also operative to process vehicle access signal (24)from receiver (34) and to generate a vehicle access control signal (42)operative to activate a vehicle access actuator (44) in order to performthe desired vehicle access function. In that regard, actuator (44) mayoperate a vehicle door lock, door, lights, horn, alarm, or other device.

[0024] Similarly, controller (36) is further operative to processvehicle activation signal (28) from receiver (34). More particularly, ina fashion well known in the art, controller (36) is operative to decryptand authenticate the vehicle activation signal (28). That is, controller(36) determines whether the code represented by the vehicle activationsignal (28) is valid. If not, controller (36) is further operative togenerate a vehicle immobilization signal (46), which is operative toactivate a vehicle immobilization actuator (48) in order to immobilizethe vehicle. In that regard, actuator (48) may operate to cut off thefuel supply to the vehicle engine, deactivate the vehicle throttle, oractivate the vehicle brakes. It should be noted that controller (36) ispreferably an appropriately programmed microprocessor, or an equivalentthereto. It should also be noted that while controller (36) preferablycomprises a single microprocessor, thereby providing cost advantages,multiple microprocessors could also be used.

[0025] Referring next to FIG. 2, a simplified block diagram of thecontrol module of the combined vehicle access, tire monitoring andvehicle immobilization system of the present invention is shown. As seentherein, and as previously described in conjunction with FIG. 1, controlmodule (32) includes receiver (34) for receiving tire data, vehicleaccess, and vehicle activation signals (18, 24, 28). As previouslydescribed, tire data signal (18) is preferably an FSK modulated signal,while vehicle access signal (24) is preferably an OOK or ASK modulatedsignal. According to the present invention, control module (32) iscapable of receiving and processing both types of signals. In thatregard, control module (32) preferably further comprises an amplifier(50) and a data slicer, preferably in the form of a comparator (52).Receiver (34) preferably includes a radio frequency (RF) integratedcircuit (not shown) that is an FSK demodulator and which includes areceived signal strength indicator (RSSI). As a result, FSK data fromthe tire data signal (18) can be accessed through a data output pin ofthe integrated circuit, and OOK or ASK data from the vehicle accesssignal (24) can be received by connecting output from the RSSI toamplifier (50) followed by comparator (52).

[0026] In such a fashion, a single RF integrated circuit can be used todetect both FSK and OOK or ASK signals depending only on the type ofincoming signal, thereby providing a low cost means for implementing theuse of both FSK (for tire monitoring) and OOK or ASK (for vehicleaccess) signals in a combined system. While the above describedembodiment is preferred, it should be noted that multiple integratedcircuits could also be employed. For example, two integrated circuitscould be used, one for receiving RF tire data and vehicle access signals(OOK, ASK or FSK), and another for receiving an LF vehicle activationsignal. Alternatively, three integrated circuits could also be used, onefor receiving an FSK modulated tire data signal, another for receivingan OOK or ASK modulated vehicle access signal, and still another forreceiving an LF vehicle activation signal.

[0027] Referring next to FIG. 3, a simplified flowchart of the combinedvehicle access, tire monitoring and vehicle immobilization method of thepresent invention is shown, denoted generally by reference numeral 60.As seen therein, the method (60) includes, as described above, providing(62) a tire monitor for mounting in a vehicle tire for monitoring atleast one tire parameter, such as tire pressure, temperature, statusand/or speed. The monitor including a transmitter which preferablyemploys frequency shift keying (FSK) modulation (although on-off keying(OOK) or amplitude shift keying (ASK) could also be used) fortransmitting a radio frequency (RF) tire data signal representinginformation concerning the at least one tire parameter. The method (60)of the present invention further includes providing (64) a hand heldremote vehicle access transmitter for transmitting an RF vehicle accesssignal for use in performing at least one vehicle access function, whichmay include operating (i.e., locking or unlocking) a vehicle door lock,activating internal and/or external vehicle lights, operating (i.e.,opening or closing) a vehicle sliding door, unlocking a vehicle trunk,activating a vehicle horn, activating a vehicle “panic” alarm, or otherfunctions. In that regard, the vehicle access transmitter preferablyemploys either on-off keying (OOK) or amplitude shift keying (ASK)modulation for encoding the vehicle access signal, although frequencyshift keying (FSK) could also be used.

[0028] Still referring to FIG. 3, the method (60) also includesproviding (66) a vehicle activation transponder for receiving aninterrogation signal and transmitting a vehicle activation signal foruse in a vehicle immobilization function. The vehicle activationtransponder may comprise a low frequency (LF), inductively coupled,battery-less transponder located in a vehicle ignition keyhead, suchthat the vehicle activation signal comprises an LF signal.Alternatively, however, vehicle activation transponder may comprise aradio frequency (RF) transponder, thereby transmitting a vehicleactivation signal (28) that is an RF signal. In yet another alternativeembodiment, an RF vehicle activation transponder may be activated totransmit an RF vehicle activation signal by an LF transponder located invehicle ignition keyhead (30).

[0029] As seen in FIG. 3, the method (60) of the present invention stillfurther includes providing (68) a control module for mounting on-boardthe vehicle, the control module including a receiver for receiving thetire data, vehicle access, and vehicle activation signals, and acontroller for processing the tire data, vehicle access, and vehicleactivation signals and generating a display signal operative to displayto a vehicle operator the information represented by the tire datasignal, a vehicle access control signal operative to perform the atleast one vehicle access function, and a vehicle immobilization controlsignal operative to immobilize the vehicle if the controller fails toauthenticate the vehicle activation signal. In that regard, the controlmodule preferably further comprises an amplifier and a data slicer, andthe receiver preferably comprises an integrated circuit including afrequency shift keying demodulator for demodulating the tire datasignal, and a received signal strength indicator for providing areceived signal strength output signal to the data slicer through theamplifier for demodulating the vehicle access signal. In such a fashion,as described in detail above, a single RF integrated circuit can be usedto detect both FSK and OOK or ASK signals depending only on the type ofincoming signal, thereby providing a low cost means for implementing theuse of both FSK (for tire monitoring) and OOK or ASK (for vehicleaccess) signals in a combined vehicle remote access, tire monitoring,and vehicle immobilization system and method. As previously described,however, a number of alternative configurations and modulation schemescould also be used.

[0030] Referring finally to FIGS. 4a-c, simplified flowchartsillustrating operations of the combined vehicle access, tire monitoringand vehicle immobilization method of the present invention are shown. Asseen in FIG. 4a, the radio frequency (RF) tire data signal istransmitted (70) by the tire monitor, and subsequently received andprocessed (72) by the control module as described in detail above todetermine any number of tire parameters, including pressure,temperature, status and/or speed. In that regard, it may be determined(74) if the tire pressure is within the recommended operating range. Ifso, a information to that effect is displayed (76) to the vehicleoperator. If not, a warning may be displayed (78) to the vehicleoperator. Such a warning display may be accompanied by an audiblesignal. As previously described, frequency shift keying (FSK) isutilized to transmit the tire data signal.

[0031] As seen in FIG. 4b, the RF vehicle access signal is transmitted(80) by the remote keyless entry (RKE) fob, and subsequently receivedand processed (82) by the control module as described in detail above todetermine the nature of the vehicle access function desired by a vehicleoperator, which may include operating (i.e., locking or unlocking) avehicle door lock, activating internal and/or external vehicle lights,operating (i.e., opening or closing) a vehicle sliding door, unlocking avehicle trunk, activating a vehicle horn, activating a vehicle “panic”alarm, or other functions. Thereafter, a vehicle access control signalis generated (84) in order to activate (86) the appropriate vehicleaccess actuator, such as a door lock or light, to perform the desiredvehicle access function. As previously described, on-off keying (OOK) oramplitude shift keying (ASK) is utilized to modulate the vehicle accesssignal.

[0032] Finally, as seen in FIG. 4c, after receipt (88) of aninterrogation signal, the vehicle activation signal is transmitted (90),such as from a vehicle activation transponder located in a vehicleignition keyhead, and subsequently received and processed (92) by thecontrol module as described in detail above to determine whether thevehicle should be immobilized. In that regard, it is determined (94)whether the code represented by the vehicle activation signal is valid.If so, no action is undertaken to disable the vehicle (96). If not, avehicle immobilization signal is generated (98) in order to activate(100) the appropriate vehicle immobilization actuator to disable thevehicle, such as by cutting off the fuel supply to the vehicle engine,deactivating the vehicle throttle, or activating the vehicle brakes.

[0033] From the foregoing description, it can be seen that the presentinvention provides a system and method for shared vehicle remote access,tire monitoring and vehicle immobilization functions that improvesperformance and reduces expense. In that regard, the present inventionpreferably employs a combined remote keyless entry (RKE), tiremonitoring and vehicle immobilization receiver, as well as a singlemicroprocessor controller. The present invention also preferably uses anon-off keying (OOK) or amplitude shift keying (ASK) modulation schemefor RKE, while preferably employing a more advantageous frequency shiftkeying (FSK) modulation scheme for tire monitoring, and provides eithera low frequency (LF) or a radio frequency (RF) link for use in vehicleimmobilization. In such a fashion, the present invention preferablycombines the above vehicle functions in one module using a singlemicroprocessor controller, yet still advantageously uses two differentmodulation schemes for tire monitoring and remote access for optimumoperation of each application, while simultaneously improving andsimplifying the vehicle immobilization function by providing an RF link.

[0034] While various embodiments of the invention have been illustratedand described, it is not intended that these embodiments illustrate anddescribe all possible forms of the present invention. Rather, the wordsused in the specification are words of description rather thanlimitation, and it is understood that various changes may be madewithout departing from the spirit and scope of the invention. Indeed,many alternatives, modifications, and variations will be apparent tothose skilled in the art in light of the foregoing description, and thepresent invention is intended to embrace all such alternatives.

What is claimed is:
 1. For use with an automotive vehicle, a combinedvehicle remote access, tire monitoring and vehicle immobilization systemcomprising: a tire monitor for mounting in a vehicle tire for monitoringat least one tire parameter, the monitor including a transmitter fortransmitting a radio frequency tire data signal representing informationconcerning the at least one tire parameter; a handheld remote vehicleaccess transmitter for transmitting a radio frequency vehicle accesssignal for use in performing at least one vehicle access function; avehicle activation transponder for receiving an interrogation signal andtransmitting a vehicle activation signal for use in a vehicleimmobilization function; and a control module for mounting on-board thevehicle, the control module including a receiver for receiving the tiredata, vehicle access, and vehicle activation signals, and a controllerfor processing the tire data, vehicle access, and vehicle activationsignals and generating a display signal operative to display to avehicle operator the information represented by the tire data signal, avehicle access control signal operative to perform the at least onevehicle access function, and a vehicle immobilization control signaloperative to immobilize the vehicle if the controller fails toauthenticate the vehicle activation signal.
 2. The combined vehicleremote access, tire monitoring and vehicle immobilization system ofclaim 1 wherein the tire monitor transmitter utilizes frequency shiftkeying modulation.
 3. The combined vehicle remote access, tiremonitoring and vehicle immobilization system of claim 1 wherein the atleast one tire parameter includes pressure.
 4. The combined vehicleremote access, tire monitoring and vehicle immobilization system ofclaim 1 wherein the remote vehicle access transmitter utilizes signalmodulation from the group consisting of on-off keying and amplitudeshift keying.
 5. The combined vehicle remote access, tire monitoring andvehicle immobilization system of claim 1 wherein the at least onevehicle access function includes operating a vehicle door lock andactivating a vehicle alarm.
 6. The combined vehicle remote access, tiremonitoring and vehicle immobilization system of claim 1 wherein thevehicle activation transponder comprises a battery-less, inductivelycoupled transponder and the vehicle activation signal comprises a lowfrequency signal.
 7. The combined vehicle remote access, tire monitoringand vehicle immobilization system of claim 1 wherein the vehicleactivation transponder comprises a radio frequency transponder and thevehicle activation signal comprises a radio frequency signal.
 8. Thecombined vehicle remote access, tire monitoring and vehicleimmobilization system of claim 7 further comprising a transponder fortransmitting a low frequency signal operative to activate the vehicleactivation transponder for transmitting the vehicle activation signal.9. The combined vehicle remote access, tire monitoring and vehicleimmobilization system of claim 1 wherein the vehicle access transmitterand the vehicle activation transponder are located in a vehicle ignitionkeyhead.
 10. The combined vehicle remote access, tire monitoring andvehicle immobilization system of claim 4 wherein the control modulefurther comprises an amplifier and a data slicer, and wherein thereceiver comprises an integrated circuit including a frequency shiftkeying demodulator for demodulating the tire data signal, and a receivedsignal strength indicator for providing a received signal strengthoutput signal to the data slicer through the amplifier for demodulatingthe vehicle access signal.
 11. For use with an automotive vehicle, amethod for combined vehicle remote access, tire monitoring and vehicleimmobilization comprising: providing a tire monitor for mounting in avehicle tire for monitoring at least one tire parameter, the monitorincluding a transmitter for transmitting a radio frequency tire datasignal representing information concerning the at least one tireparameter; providing a handheld remote vehicle access transmitter fortransmitting a radio frequency vehicle access signal for use inperforming at least one vehicle access function; providing a vehicleactivation transponder for receiving an interrogation signal andtransmitting a vehicle activation signal for use in a vehicleimmobilization function; and providing a control module for mountingon-board the vehicle, the control module including a receiver forreceiving the tire data, vehicle access, and vehicle activation signals,and a controller for processing the tire data, vehicle access, andvehicle activation signals and generating a display signal operative todisplay to a vehicle operator the information represented by the tiredata signal, a vehicle access control signal operative to perform the atleast one vehicle access function, and a vehicle immobilization controlsignal operative to immobilize the vehicle if the controller fails toauthenticate the vehicle activation signal.
 12. The combined vehicleremote access, tire monitoring and vehicle immobilization method ofclaim 11 wherein the tire monitor transmitter utilizes frequency shiftkeying modulation.
 13. The combined vehicle remote access, tiremonitoring and vehicle immobilization method of claim 11 wherein the atleast one tire parameter includes pressure.
 14. The combined vehicleremote access, tire monitoring and vehicle immobilization method ofclaim 11 wherein the vehicle access signal comprises a radio frequencysignal and the remote vehicle access transmitter utilizes signalmodulation from the group consisting of on-off keying and amplitudeshift keying.
 15. The combined vehicle remote access, tire monitoringand vehicle immobilization method of claim 11 wherein the at least onevehicle access function includes operating a vehicle door lock andactivating a vehicle alarm.
 16. The combined vehicle remote access, tiremonitoring and vehicle immobilization method of claim 11 wherein thevehicle activation transponder comprises a battery-less, inductivelycoupled transponder and the vehicle activation signal comprises a lowfrequency signal.
 17. The combined vehicle remote access, tiremonitoring and vehicle immobilization method of claim 11 wherein thevehicle activation transponder comprises a radio frequency transponderand the vehicle activation signal comprises a radio frequency signal.18. The combined vehicle remote access, tire monitoring and vehicleimmobilization method of claim 17 further comprising providing atransponder for transmitting a low frequency signal operative toactivate the vehicle activation transponder for transmitting the vehicleactivation signal.
 19. The combined vehicle remote access, tiremonitoring and vehicle immobilization method of claim 11 wherein thevehicle access transmitter and the vehicle activation transponder arelocated in a vehicle ignition keyhead.
 20. The combined vehicle remoteaccess, tire monitoring and vehicle immobilization method of claim 14wherein the control module further comprises an amplifier and a dataslicer, and wherein the receiver comprises an integrated circuitincluding a frequency shift keying demodulator for demodulating the tiredata signal, and a received signal strength indicator for providing areceived signal strength output signal to the data slicer through theamplifier for demodulating the vehicle access signal.